The impact of the World Trade Center (WTC) attack on those directly exposed to it is long-lasting and affects their day-to-day living. Due to the proximity of Chinatown to the disaster site and a large number of South Asians working in the WTC and nearby buildings, Asian Americans (AA) constituted a sizeable proportion of those exposed to the attack. The trauma has created major challenges for mental health professionals. While dozens of studies have investigated the mental health impact of the attack on the survivors, few have included Asians in their study samples. Objectives: this investigation targets the Asian community and attempts to assess the mental health impact of the trauma to individuals directly exposed to the attack, and to understand their mental health service use patterns so as to more effective in reaching out to them. The literature has indicated that due to cultural impact AA tend to emphasize the somatic expression of emotional distress, attribute immense stigma to mental illness itself and to mental health service use. As a result, delay in treatment and the use of medical care to address physical symptoms of emotional distress is common. Since 71% of AA in New York City are immigrants, language barriers, lack of knowledge about services, and the paucity of bilingual services also created practical barriers to service use. Acculturation stress and the prolonged economic setbacks around Chinatown following the attack also aggravated the stress they experienced. PTSD resulting from recent trauma has hardly been studied among AA. The WTC attack offers a unique test case to understand the impact of PTSD among AA, to see if the widely recognized disaster had ameliorating effect on help-seeking, and if 9/11-designated programs succeeded in reaching out to AA. Design & Methods: to address the knowledge gap, secondary data analyses will be conducted using the large study of WTC Health Registry focusing on survivors and rescuers of the attack. The Registry has 3 waves of data with a large Asian sample of 4,885. The longitudinal study spanning over 9 years also extends the horizon of existing studies. Mental health impact and mental health and medical care service use among AA will be studied and compared against the Whites as a reference group. Subsample analyses of the rescue and recovery workers and Chinese Americans would also be done to provide an occupational focus and to examine the largest Asian ethnic group. Specific aims of the study are: 1)To assess the short-, medium-, and long-term mental health impact of the WTC attack on AA, its course and related risk factors, and to compare to those of the Whites; 2) To examine patterns of mental health service use and identify the enabling factors vs. barriers affecting service use among AA, and compare them with these factors among Whites, to better understand racial disparities; 3)To examine the relationship between psychological distress and medical care use among AA and Whites, and the impact of comorbidity of psychological and physical distress on their use of medical care service, to illuminate processes underlying racial disparities.